1,721,172 research outputs found
Campania region grapevine patrimony: a determination of the heat requirement of 19 nearly all native cultivars
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Optimized Design of a Cotton Wool Making Plant
No full textWith this study the optimized design of a plant for the production of cotton wool with a productive capacity of 1760 ton/year has been performed. Kept account of the different processes that is necessary to perform, machineries that realize the productive processes to make have been individuated. Besides they have been considered the carding machines and particularly the Cylinder and Hat Carding machines, underlining the positive and negative sides of it by a study of the carding action performed by such machines. Finally, it has opportunely been designed the carding department. It has been performed then the sizing of the whole plant, starting with the machines choice, on the basis of the determined productive capability of the considered plant. Insofar the beating department has been designed, on the basis of workmanship demands. It has been studied the bleaching phase determining the machines that realize such process. For the drying process a study has been performed aimed to the optimal management of the thermodynamic exchange to be performed, with minimum energy cost. Finally for the wrapping phase, it has been considered a procedure that allowed the reduction at the minimum values of the encumbrance volumes of the final product. Subsequently the sizing of the stores has been realized for raw material and final products
Performance Evaluation of Pneumatic Machines for Hazelnut Harvesting
No full textIt has been considered an hazelnut harvest technique by hazelnuts aspiration from the soil, and a comparison with the characteristics of the crop and of the soil, with which the considered machines have to interact, has been performed. This technique has broadly spread in Campania Region and for it, it is not required a meadow around the trees. After having performed some tests for the considered harvest technique, the characteristic parameters of working capacity, working quality and energy costs have been evaluated. Further, it has been faced the problems due to the soil dusts. to identify a filtering system capable of reducing the great amounts of dusts introduced in the environment during the process of hazelnuts picking up by means turbo-aspirating machines. The main types of dust removers for medium-thin dusts have been studied and examined; a comparative exam proved the mechanical removal by cyclone (centrifugal dust separator) to be the most effective. Therefore, two prototype filters were examined, each consisting of four cyclones with a turning diameter of mm 350 and mm 250 respectively. Field tests showed the effectiveness of the system; the 350 mm multi-cyclone proved to have a dust removing capacity of 90%, with no reduction in performance caused by the dust that goes through it, while the 250 mm removes 93.75%, with a reduction in performance of approximatevely 30%. However, it would be a mistake to give preference to the former over the latter, as its better performance does not compensate, in terms of environment hygiene, the 3.75% difference which, though seemingly slight, represents a further reduction of 50% of the thinner dust contained in the atmospher
Optimized Use of Grape Cryomacerating Plants
No full textIt has been performed a study of a plant for the grape cryo maceration, evaluating the different operational thermodynamic conditions obtained for three quantity of a same typology of considered grapes and fixing the process final temperatures at 12, 10, 8 and 6 °C, all that to be able to evaluate and to compare the products obtained under the conditions considered. For a best understanding of the problem, it has been set up a numerical model of the different products involved in the cryo-maceration process so that to be able to face from the theoretical-numerical-experimental point of view the whole research to be developed. Such model has been used during the numerical simulation of the process that also allows a best set up of the considered plant, over that to achieve an optimization of its use. Numerical analysis has been performed with the aid of the computational code CFD (Computational Fluid Dynamics) Fluent. In this way it has been possible to obtain the temperatures and velocity distributions of the fluid inside the delivery pipe under the different considered operative conditions. Such distributions have found a good comparison with the experimental tests performed on the plant by using transducers that, applied on the delivery pipe, they have allowed the evaluation of the temperature distribution. The obtained results can be used to a possible optimization of such types of plant, in sight of the oenologist demands to achieve continuous improvement of the final product quality
Combined use of Finite Element and Equivalent Circuit Modeling for System-Level Simulation of Integrated Capacitive Micromachined Ultrasonic Transducers (CMUT)
No full textThis paper proposes the combined use of Finite Element Modeling (FEM) and Equivalent Circuit Modeling (ECM) to describe the nonlinear electromechanical and acoustic behavior of a CMUT in an integrated circuit simulation environment. CMUT ECM lumped parameters are computed by FEM simulations. The proposed method is implemented in LTSpice, and validated by comparing ECM and FEM static, small-signal harmonic, and large-signal transient simulation results. The model was then applied to the performance assessment of the CMUT coupled to a realistic integrated transceiver configuration by computing TX efficiency and noise figure. The proposed approach allows accurate large-signal analysis of CMUTs interfaced to ultrasound front-end circuits by considering non-ideal characteristics of the system, such as the pulser nonlinearities
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